This invention relates to vehicle tires, and, more particularly, to pneumatic vehicle tires having "run-flat" capability.
The art has long recognized the desirability of a "run-flat" pneumatic vehicle tire, that is, a pneumatic tire which retains the ability to support the vehicle in the event of loss of air from the tire, and to this end many structures and devices have been suggested. A popular approach to imparting "run-flat" capability is to provide the tire with an internal device in the form of a ring of sufficient height and width to rotatably support the vehicle in the event of collapse of the tire. The ring may be solid or a porous rigid or flexible member simply positioned upon and supported by the tire rim. However, since the outer circumference of the insert ring must be spaced only a short distance from the treadwall of the inflated tire carcass, devices of this type tend to be heavy and to present difficulties when being installed within the tire carcass and/or when the tire is subsequently mounted upon the rim. In certain cases, special rims such as "split" or two-piece rims are required for mounting of these devices.
In other run-flat designs, the ring does not extend entirely to the rim, but rather is supported by various arrangements which attempt to lessen the overall weight of the run-flat device and/or to simplify its insertion and mounting. The need nevertheless remains for a run-flat device which is light in weight yet is practical from the standpoint of being easily installable within the tire and which does not interfere with the normal mounting of the tire.